This letter presents results of high structural quality epi/oxide boundaries of selective epitaxy grown on (100) oxide patterned Si wafers by ultralow pressure chemical vapor deposition from SiH4/H2at 800 °C using growth‐sputter cycles. The epitaxial films were characterized by cross‐sectional transmission electron microscopy and Nomarski optical microscope. About 2.1 &mgr;m silicon epitaxy was grown on the exposed silicon windows with about 0.27 &mgr;m lateral epitaxial growth over the oxide near {011} epi/oxide sidewalls. Almost no lateral epitaxial overgrowth was observed near {010} sidewalls. The epi/oxide boundary and the epitaxy grown over the oxide were found to be of high structural quality and defect‐free.